Electronic device



o@ 15 1946- A. G. THOMAS ELECTRONIC DEVICE Filed Jan. 27, 1944ililiilllliliillllll| E. f.. G QL Patented ct. 15, 1946 UNITED STATESPATENT OFFICE 2,409,454 ELECTRONIC DEVICE Albert G. Thomas, Lynchburg,Va.

Application January 27, 1944, serial No. 519,924

(ci. 25o-41.5)

21 Claims.

This invention relates to electronic devices and particularly toreproducers for copying letters, maps, drawings, photographs and thelike.

Many reproclucers have been marketed depending upon various processesSuch as gelatin images, photographic reproductions, blueprinting, andothers. All kof these methods are relatively slow, however, and aresomewhat cumbersome in operation; besides requiring liquid chemicals orvapors for development. In contrast, my electronic reproducer is fast,requires no chemicals, and provides accurate copies in small or largequantities in a minimum of time.

A primary object is to provide an electronic reproducer that willfurnish copies of drawings, pictures, letters, and the like atreasonable cost and quickly.

Another object is to provide an electronic reproducer that will beautomatic in operation; producing a given number of copies after beingset properly.

A further object is the provision of an electronic reproducer which canbe used to make copies of different originals, without breaking thevacuum. n

An additional object is to provide an electronic reproducer thephotosensitive surface of which is protected from harmful atmospheric orother innuences when the Vacuum is broken.

Other objects will appear in the following description.

In the drawing:

Figure 1 is a side elevation, in part section, of my electronicreproducer, showing a lamp, the glass or other transparent container,driving motor, evacuating pump, and other associated parts,

Figure 2 is a fragmentary side elevation, in part section, of avariation of my electronic reproducer in which the photosensitivesurface is covered before air is admitted to the container.

Figure 3 is a plan view of a driving motor with automatic cut-ofi tostop the motor after a predetermined number of copies are made.

Figure 4 is a fragmentary end View, in part section, of a selenium typeof reproducer.

In Figure 1, container I is made of glass or other transparent material,although wall 2 only can be transparent if desired. This container hastop 3 which may be pressed tightly against the upper edge of container Iin air-tight manner, by means of cross plate 4 which is provided withsuitable holes through which end-threaded rods 5 and 6 pass. Thumb nuts1 and 8 may be screwed down on rods 5 and 6 to apply pressure 2 to plate4 and consequently to top 3 to eiect a seal. A suitable gasket may beprovided. The bottom ends of rods 5 and 6 are screwed into base 9 whichmay be of any suitable material.

Top 3 may be hinged or clamped to container I so that plate 4 and rods 5and 6 may be eliminated. Any suitable clamp may be used but shouldpreferably be quickly manipulated. In this case it would be preferableto have wall 2, or a part thereof, of glass and the rest of thecontainer, including top 3, of metal. A suitable seal between the glassand metal would be provided.

The inner surface, or at least a portion of the inner surface of `wall2, is covered with semitransparent photo-emissive surface I0 which 1sadapted to emit electrons in proportion to the intensity of light raysfrom electric lamp I I held at the focus of parabolic reilector I2 whichis fastened to support I3 xed to base 9. Any suitable source of parallellight rays may be used however, or in Vsome cases even illuminationthrough ground glass could be used.

Surface I may be made by depositing a thin layer of silver on the innerglass surface of wall 2. Then a thin layer of caesium or otherphotoemissive material may be deposited over the silver by evaporationor otherwise. The top surface of the silver may be oxidized beforedepositing the caesium, by glow discharge or in other mannel'.

The silver is electrically connected to conductor I4 which leads to thenegative pole of battery or other potential source Iia, the positivepole of which is connected to nickel or other metal plate I5 by means ofconductor I6. Plate I5 serves as the anode and is fastened to uprightI'I by means of posts I8. Upright II may be of insulating material andis suitably fastened to base I9 which may be set upon or fastened tocontainer base 20.

The photo-emissive surface IQ may consist of a variety of materials suchas potassium hydride, silver, caesium-on-silver, or the like. It ispreferable that this photo-emissive surface be of such material that itwill not be materially damaged by exposure to the atmosphere. Since manymetals eject electrons upon exposure to light, a variety of usefulsubstances are available. The methods of making photo-emissive surfacesare well known and consequently will not be described in detail.

Upright I 'I and a similar slotted upright on the opposite side of baseI9 support rod 2I which carries spool 22 around which electricallysensitive paper 23 is wound. This paper is fed over guide rollers 24 and25 supported on arms 26 and 21 and similar arms attached to upright I1at the opposite end of Spool 22. The paper may rub against anode plate Iif desired, or may be slightly separated from it as shown. Paper 23 iswound upon bottom spool 28 which is rotated by shaft 29 having bearingin uprights I1. Gear 30 is fastened to the end of shaft 29 and is meshedwith gear 3| which is driven by reduced speed motor 32 fastened to baseI9.

Motor 32 is supplied electrical energy through conductor 33, sealed incontainer I, and through conductor 34, similarly sealed and leading tobrush 35 pressing against metal slip ring 36 a short section 36a ofwhich is made of porcelain, mica, or other insulating material. Brush 38also presses against slip ring 36 and is connected to a pole of switch39 the other pole of which connects to line wire 40. Energy is thereforesupplied to motor 32 when Switch 39 is closed and when the metal portionof slip ring 36 bridges the brushes 35 and 33.

Slip ring 36 and smaller slip ring 4I are rotated at reduced speed bymotor 42, by means of epicyclic or other suitable reduction gears Motor42 drives evacuating pump 43 which removes air or other gas fromcontainer I through connected pipe 44, which is sealed in container I;when valve 45 is open. The air is exhausted through outlet pipe 46.This` pump may be of any suitable type and may include an auxiliary highvacuum mercury vapor or similar pump. The pump should have suiiicientcapacity so that container I can be evacuated to the desired lowpressure in a minimum of time, within several minutes or lesspreferably.

Motor 42 is supplied energy through conductors 41 and 48. a suitableswitch being provided.

Brush 49, supported on the motor frame, is connected with Wire leadingto lamp II. Brush 49 presses against slip ring 4I which is of insulatingmaterial such as mica, fibre, bakelite or the like, except forrelatively short arcuate portion 5I which is made of metal. Thisconducting portion is placed radially in alignment with insulatingportion 36a of slip ring 36, so that lamp II will be lighted when motor32 is stationary. Brush 4B, supported on the motor frame, also pressesagainst slip ring 4I and is connected to line wire 52. The othercooperating line wire 53 is connected to the other terminal of lamp IIby means of wire 54 which may be passed through base 9.

Spring clips 55 and 56 are fastened to the outside of Wall 2 and serveto hold letter 51 or other object to be copied, flat against thesurface. A glass plate may be placed over letter 51 to press it againstwall 2, if desired.

Motors 32 and 42 may be synchronous motors or of any suitable type. Themotor speeds or reduction gearing, or both, should be so chosen thatpaper 23 will be moved through the maximum frame length or effectiveimage length, when slip rings 36 and 4I are rotated through onerevolution.

While motor 32 is shown at bottom, it is preferable that spool 28 beplaced at the top so that the exposed paper can be easily reached. Thewhole assembly could be slipped out if desired; flexible or slidingmotor contacts being provided for that purpose.

Paper 23 may be of any suitable electrically Teledeltos. In fact, it isnot essential that it be electrically sensitive since the electrons canbe made to burn their images in the paper or other material.

In operation, a roll of the paper on spool 22 is placed in the deviceand the other end is attached to shaft 29 of spool 28. Then top 3 isplaced in position and thumb nuts 1 and 8 are screwed down to pressplate 4 against top 3 to effect an air-tight seal. Valve 45 is thenopened and motor 42 is energized to evacuate container I quickly. Whenthe desired degree of vacuum is reached, as indicated by a suitable gageor after a predetermined time interval, letter or drawing 51 is placedas shown and switch 39 is closed. When this happens motor 32 will movepaper 23 through a frame length, then will stop for a brief periodduring which time lamp II will be lighted so that the light Will passthrough letter 51 and will cause an electron pattern to be liberatedfrom photo-emissive surface I0, the density of the electronscorresponding in inverse relation to the opacity of the letter 51. Theelectron image will be accelerated by positively charged anode I5 sothat an image will be made on paper 23, by electron bombardment. Thisimage can be made visible and permanent or the electrically chargedcondition of the paper can be used to affect the rate of taking up inl:if a printing art process is desired.

As the motors continue to revolve, a succession of copies Will be made.After the desired copies are made, letter or other object 51 can bechanged if desired Without breaking the seal of container I.

In case letter 51 is not translucent, a reflected image can be projectedon wall 2, by means oi a suitable lens system.

When the desired copies are obtained, switch 39 is opened and motor 42is similarly stopped. Thumb nuts 1 and 8 are then screwed up so that top3 can be lifted and the exposed paper bearing the images can beremo-ved.

It is obvious that paper 23 could be moved by solenoid action, with acooperating ratchet. Many other variations can easily be made.

In fragmentary Figure 2, container 58 has top 59 and two sealed-in pipes60 and 6I which may be connected to an exhaust pump and a source ofYinert gas such as argon, nitrogen, helium or the like, respectively.

Photo-emissive surface 62 on transparent plate 63 serves as the cathodeto produce an electron image pattern which is accelerated toward anode64. Inclined rubber or other rim 65 is provided around the periphery ofplate 63 so that inclined plate 66 will seal off photo-emissive surface62 from the atmosphere when plate 66 is pressed down against rim 65.Plate 66 is moved vertically by means of integral rack B1 andcooperating pinion 68 driven by motor 69 which may be suitablyenergized. When the container has been evacuated, plate 66 is raised tothe position shown, before use. As a further precaution against damageto surface 62, inert gas may be admitted to the container through pipe6I when top 59 is removed. This gas may be directed against surface 62.The letter to be copied may be placed against plate 63 inside, ifdesired.

In Figure 3, motor 10 may be used to drive the paper or the pump. Collar12 is provided with ratchet or pin 13 which may be adjusted to allow thecollar to be slipped laterally on threaded motor shaft 1I so that collar12 may be set, by means of attached pointer 14 and cooperating scale 15fastened to motor 10, to allow a predetermined number of copies to bemade before collar 12 is moved by rotating shaft ll until it strikes andopens switch 'I6 which stops the motor.

In Figure 4, metal screening 'Il' is connected to one pole of battery-orother current source 18 the other pole of which is connected to metalplate 19. Thin selenium plate 80 is pressed against preferably moistelectro-sensitive paperfl which is pressed against plate 79. If then aletter is pressed against screening 11 by means of a glass plate orotherwise, then the current conducted by the elemental areas of theselenium will be according to the opacity of the letter so that an imagewill be made on paper Bl. Light is, of course, directed through theletter.

-Many changes of detail-can, of course, be made without departing fromthe general principles I have disclosed. For instance, electricallyenergized magnets or solenoids can be used to force plateGS against rim65 when it is desired to protect surface 62. The energization of themagnets can be made automatic when the top 59 is removed, or before.Likewise, the introduction of inert gas can be made automatic.

In the specificationk and claims, the word light denotes radiation ofany suitable kind, whether of lvisible wavelengths or invisible such asinfra-red, ultra-violet, X-ray, or other radiation.

What I claim is:

l. The method of making reproductions of typewriting, printed matter,drawings or the like, comprising, forming a light image of the object tobe copied, transforming said image into an electron image, and directingsaid electron image against material adapted to be visibly changed incharacter or color byelectron bombardment.

2. The method of making reproductions of typewriting, printed matter,drawings or the like, comprising, forming a light image of the object tobe copied, transforming said image into an electron image, and directingsaid electron image against material adapted to be chemically changed byelectron bombardment visibly to reproduce said image in or on saidmaterial.

3. An electronic device comprising, a container having a, lighttransmitting wall, a closure for said container, a translucent coatingof photoemissive material on at least a portion of the inner surface ofsaid wall, an electrically conducting plate substantially parallel withsaid wall, electrical conductors connected with said coating and saidplate, electrical means connected With said conductors for charging saidplate positively with respect to said coating, a pair of rollers withinsaid container, means to support said rollers, and electrical meansoperatively connected with at least one said roller to rotate saidroller.

ll. An electronic device comprising, a container having a lighttransmitting wall, a closure for said container, a translucent coatingof photoemissive material on at least a portion of the inner surface ofsaid Wall, an electrically conducting plate substantially parallel withsaid wall, electrical conductors connected with said coating and saidplate, electrical means connected with said conductors for charging saidplate positively with respect to said coating, a pair of rollers withinsaid container, means to support said rollers, electrical meansoperatively connected with at least one said roller to rotate saidroller, and a sheet of material which may be visibly and permanentlychanged by electron bombardment adapted to be moved between said coatingand said plate by means of said1 rollers.

5. An electronic device comprising, a container having a lighttransmitting wall, a closure for said container, .a translucent coatingof photoemissive material on at least a portion of the inner surface ofsaid wall, an electrically conducting plate substantially parallel withsaid wall, electrical conductors connected with said coating and saidplate, electrical means connected with said conductors for charging saidplate positively with respect to said coating, a pair of rollers withinsaid container, means to support said rollers, and electrical meansoperatively connected with at least one said roller to rotate saidroller in a succession of predetermined steps.

6. An electronic device comprising, a container having a lighttransmitting wall, a closure for said container, a translucent coatingof photoemissive material on at least a portion of the inner surface ofsaid wall, an electrically conducting plate substantially parallel withsaid wall, electrical conductors connected'with said coating and saidplate, electrical means connected with said oonductors'fo-r chargingsaid plate positively with respect to said coating, a pair of rollerswithin said container, means to support said rollers, electrical meansoperatively connected with at least one said roller to rotate saidroller, and an evacuating pump connected with said container.

7. An-electronic device comprising, a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said lm, electricalconductors connected with said film and said element, means electricallyconnected with said conductorsvfor establishing an electrostatic fieldbetween them, and pumping means connected with said container to causeevacuation thereof.

8. An electronic device comprising, a containel1 having a closuretherefor, at least a portion of said container being oflight-transmitting character, a m o-f photoemissive material within saidcontainer and positioned to receive light passing through said portion,an electrically conducting element adjacent said film, electricalconductors connected with said nlm and said element, means electricallyconnected with said conductors for establishing an electrostatic fieldbetween them, pumping means connected with said container to causeevacuation thereof, a sheet of material of a character to be visibly andpermanently changed by particle bombardment positioned between said lmand said element, and means within said container for moving said sheet.

9. An electronic device comprising, a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conduct-r ing element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between themVpumping means connected with saidcontainer to cause evacuation thereof, a sheet of material of acharacter to be visibly changed by particle bombardment positionedbetween said nlm and said element, and means for moving said sheetthrough predetermined displacements.

l0. An electronic device comprising, a container having a closuretherefor, atleast a portion ofv said container being oflight-transmitting.

character, a film of photoemissive material within said container andpositioned to receive light pass ing through said portion, anelectrically conducting element adjacent said film, electricalconductors connected with said film and said element, means electricallyconnected with said conductors for establishing an electrostatic fieldbetween them, pumping means connected with said container to causeevacuation thereof, a sheet of material of a character to be visiblychanged by particle bombardment positioned between said film and saidelement, and means including a motor within said container for movingsaid sheet.

11. An electronic device comprising, a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them. pumping means connected with saidcontainer to cause evacuation thereof, and illuminating means fastenedto said device to direct light through said portion and said film.

12. An electronic device comprising, a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, illuminatingr means fastened tosaid device to direct light through said portion and said film, andautomatic means connected with said illuminating means to causeillumination of said film for predetermined intervals.

13. An electronic device comprising a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, a sheet of material of acharacter to be visibly changed by particle bombardment positionedbetween said film and said element, and automatic means for moving saidsheet through a succession of predetermined displacements withpredetermined stationari7 intervals between said displacements.

14. An electronic device comprising a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, illuminating means associatedwith said device to direct light through said portion and said film, asheet of material of a character to be visibly changed by particlebombardment positioned between said film and said element, automaticmeans for moving said sheet through a succession of predetermineddisplacements, and automatic means to affect said illuminating means todirect light through said film during stationary intervals of said sheetbetween intervals of said displacements.

15. An electronic device comprising a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, and automatic means to time theemission of electrons from said film.

16. An electronic device comprising a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, and means within said containerto cover said film to prevent exposure to air when said closure isopened.

17. An electronic device comprising a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a film of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said l element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, an element within said containerto cover said film to prevent exposure to air when said closure isopened, and electrical means to actuate said element.

18. An electronic device comprising a container having a closuretherefor, at least a portion of said container being oflight-transmitting character, a nlm of photoemissive material withinsaid container and positioned to receive light passing through saidportion, an electrically conducting element adjacent said film,electrical conductors connected with said film and said element, meanselectrically connected with said conductors for establishing anelectrostatic field between them, pumping means connected with saidcontainer to cause evacuation thereof, and means connected with saidcontainer for introducing gas therein to protect said film when saidclosure is opened.

19. The method of making reproductions, said method comprising the stepsof directing light against an object to be copied to produce alightand-shadow image thereof, allowing said image to strike aphotoemissive surface to cause emission of an electron pattern inaccordance with said image, and accelerating said electron patternagainst material of a character to be visibly 9 and permanently changedby said electron pattern in accordance therewith..

20. The method oi protecting a photoemissive surface of an electronicdevice having a container adapted to be opened to atmosphere, saidmethod comprising sealing 01T said surface from the atmosphere Whilesaid container is open.

10 21. The method of protecting a phctoemissive surface of an electronicdevice having a container adapted to be opened to atmosphere, saidmethod comprising surrounding said surface with protesting gas Whilesaid container is open.

ALBERT G. THOMAS.

